Heck, the 2012 first-round draft pick even delivered a welcome-to-the NFL moment to the Chargers' first draftee of 2013.

It was the first full-squad practice under new head coach Mike McCoy.

Ingram, playing left outside linebacker, set up in apparent pass coverage. Then, anticipating the snap, he darted forward and raced by right tackle D.J. Fluker, who couldn't slide outside fast enough.

The "touch" sack against Philip Rivers didn't mean that Ingram, the 18th pick last year, was headed toward a big season.

But when Ingram then met with strongside linebacker Jarret Johnson, a 10-year pro who is a mentor, the two broke into grins.

Now comes word that Ingram, 24, suffered a torn anterior cruciate ligament on Tuesday. The injured left knee could cost him the 2013 season.

It's a body blow, to both Ingram and the Chargers. Yes, Ingram notched just one sack last year. He appeared in all 16 games, though, giving him a sense of the NFL game. He went into the recent offseason saying the right things. "I need to work on everything -- everything," he told me the day after the season ended. "That's what I'm going to do."

You wouldn't say Ingram came to the NFL as the most mature of rookies. But people evolve at different speeds.

"Once he grows up and really understands the game and how to prepare, this kid is going to be a beast," Johnson said while packing for the winter.

The Chargers were counting on Ingram to rev up their pass rush. They let Shaun Phillips and Antwan Barnes leave in free agency, and expected Ingram to make a big jump this year, much like Corey Liuget, their top pick of 2011, made last season.

The Chargers need another first-round draftee, Larry English, to finally live up to being selected 16th in 2009. English, sidetracked by several injuries, boasts only four career starts and 8.5 sacks in four seasons. It's probably now or never for him. Johnson is a complete player who is adept at setting the edge. But the Chargers lack an edge rusher who will make opponents nervous. It's only May, but that's a troubling prospect. It's also opportunity for English and rookie Tourek Williams, a sixth-round draft pick. Meantime, another challenge confronts rookie general manager Tom Telesco, who in addition to shopping for a left tackle will be searching for another outside linebacker.